Devices and techniques used to improve physical fitness often attempt to isolate specific muscles or muscle groups wherein the isolated muscle or muscles are repeatedly moved in a specified range of motion. Resistance training protocols in particular typically direct a subject to use their own body weight as a source of resistance against a prescribed movement, e.g., a push up or a pull up. External weights may also be used by a subject to increase the resistance load that the subject works against in executing the prescribed motion.
Humans have long recognized the beneficial interrelationships between exercise, muscle fitness, and health. Various exercise techniques and devices have been provided to promote healthy muscle tissue and development, to assist in metabolic regulation, and to improve the general function and overall appearance of the body. However, some muscles and muscle groups of the human body are easier to exercise in isolation than other muscles. The bicep muscles of the human arm, for example, are generally easier to engage in resistance training than the abdominal muscles. In particular, designing a resistance training exercise with the intent to strengthen the human abdominal muscles requires that attention be paid to the risk of injury to the human verterbrae.
The categories of exercise used to improve muscle fitness include, for example, isometric, isotonic, and isokynetic. Isometric exercise may strengthen muscles through contraction of the muscles. Isotonic exercise may strengthen through the contraction and relaxation of muscles, as the instant muscles flex and extend. The incorporation of weight (such as free weights or body weight) into such exercises may increase the benefits of exercise by the addition of resistance training dynamics. An example of weight-bearing exercise, i.e., resistance training, can be seen in a simple pushup, during which various groups of muscles in the arm contract and release during each pushup while bearing at least a portion of the body's weight.
Isokynetic exercise may strengthen muscles through the use of various systems such as weight machines, whereby various pulleys and weight stacks add exertion, resistance, and weight to pulling, pushing, or lifting exercises.
Such techniques and equipment are often directed to specific areas of the human body in an effort to target specific muscles groups. One oft-targeted area, for example. includes the muscles located in the abdominal region of the body, generally between the thorax and the pelvis. For example, the rectus abdominus is a long, flat muscle that extends vertically the entire length of the abdomen and is enclosed in a sheath that holds the rectus abdominus in position but does not restrict movements during its contractions.
The abdominal muscles (hereinafter. abs) flex the vertebral column, i.e., the spine, particularly in the lumbar portion, and may draw the sternum, or breastbone, toward the pubis. Certain abs may also tense the abdominal wall and aid in compressing the contents of the abdomen and enhance prevention of strain or injury to the lower lumbar region of the spine. Hence, strong, well-developed “abs” may be directly linked to the efficient mobility and functionality of the body as well as provide a widely coveted appearance of “flat abs”.
A number of difficulties exist, however, with respect to increasing, developing and maintaining the muscular tone and condition of abs. One issue surrounds the relative location of the abs with respect to exercise equipment. The torso region of the body is not easily given to manipulation of exercise equipment as are, for example, the arms. Various muscles groups of the chest, arms and back may be targeted by simply grasping and manipulating free weights or weighted/stretching components of various machines or by simply performing push-ups or pull-ups.
The relative involvement of antagonistic groups of muscles during movement of the torso, and the tendency for one group to dominate another creates an additional challenge for exercise equipment and techniques intended to strengthen the abs. Such involvement may be antagonistic wherein one group of muscles tends to oppose another in motion. For example, when certain groups of muscles are fully engaged it may be difficult or impossible to fully engage a muscle or muscle group antagonistic to the engaged group.
This difficulty may be illustrated by way of considering the hamstring and gluteus maximus (gluts) versus the hip flexors. When the hamstring and gluts contract or engage, the hip flexors generally extend and lengthen, and the opposing functions serve to straighten out the vertebral column into an erect posture. When the hip flexors engage or contract, the hamstrings and gluts generally tend to extend and lengthen. The opposing functions and activities of the hamstrings and gluts versus the hip flexors serve to bend the hips moving the upper body forward and away from an erect pose. In other words, when one muscle group is engaged, that very engagement may serve to inhibit engagement of the other antagonistic muscle or muscle group, and vice versa.
Additionally˜certain groups of muscles dominate others; i.e. the dominant muscles tend to engage more quickly and to greater degree than submissive groups. For example. the iliopsoas muscle, or hip flexor, is a powerful flexor muscle of the thigh at the hip joint. If engaged, the hip flexor may act as important flexors of the trunk or the hip, as in sitting up from a supine position. As the hip flexors are both dominant and antagonistic with respect to the abdominal muscles, the hip flexors tend to engage before the abs, and thereby tend to inhibit some or all of the contraction of the abs. During a typical sit-up or “crunch” exercise directed to the abs, the hip flexors may actually engage and provide the underlying functionality to translate the body from a first position to a second position with little or no engagement of the abs, thus undermining the full ability of the abs to contract and resulting in minimal exercise efficiency of the abs.
Another issue affecting the design of resistance training exercises for the abs involves the range of motion of a muscle or a group of muscles. The most effective exercise typically includes exercise of a muscle across a full range of motion of the selected muscle. The full range of motion typically includes a first position of full extension of the muscle to a second position of full contraction of the muscle. Certain muscle groups, such as the abs, present some difficulty during exercise in achieving muscle movement across the full range of motion. For example, during a sit-up or “crunch” exercise, the exerciser typically adopts an initial supine position, wherein the spine forms a 180 degree angle relative to a surface on which the exerciser's torso lies. In this position, the abs are not fully extended and therefore only a truncated contraction of the abs can be achieved. To fully extend the abs, one must hyperextend the spine, arching it backwards. Such a hyperextension of the spine, however, exposes various areas of the body to injury. For example, a hyperextension of the spine exerts an excess load of body weight on the lumber region, or lower back, which may result in injury, pain. or strain. In addition, such a hyperextended position to fully extend the abs may be difficult to achieve. For example, one might perform a “backbend” position; i.e. feet planted and arms extended overhead, arching the back until the palms of the hands touch the ground. This position, however, is difficult—perhaps impossible—for a majority of persons to achieve. Further, contraction of the abs when in a back bend pulls the body upright off the ground, but in doing so again applies a great deal of weight upon the otherwise unsupported lumbar region, thereby exposing one to a significant risk of injury and pain.
The human spine is made up of thirty three irregularly shaped bones called vertebrae. Each vertebra has a hole in the middle through which the spinal cord runs. The spine can be divided into five different regions, to include: (a.) seven cervical vertebrae that support the human to head and neck and allow a human to nod and shake his or her head, (b.) twelve thoracic vertebrae that anchor the human ribs, (c.) five sturdy lumbar vertebrae that carry most of the weight of the human upper body and provide a stable centre of gravity during locomotion, (d.) five vertebrae fused to form the sacrum that partially constitute a back wall for some of the muscles, tissues and organs that are supported by the pelvis, and (e.) a coccyx is made up of four fused vertebrae. The coccyx is generally held to be an evolutionary remnant of the tail found in many other vertebrates.
The Method of the Present Invention addresses the needs of physical therapists, physical trainers and other health service providers to design and teach resistance training exercises that reduce the likelihood of damage to the spine when performed by their clients and patients.